Scribing tool



Nov. 6, 1945.

A. J. LYNEX 2,388,361 r SCRIBING TOOL Filed Aug. 5, 1944 INVENT0R.-

ALFRED J. LYNEX ATTORNEY Patented Nov. 6, 1945 SCRIBING TOOL Alfred James Lynex, Buffalo, N. Y., assignor to Curtiss-Wright Corporation, a corporation of Delaware Application August 5, 1944, Serial No. 548,243

1 Claim.

This invention relates to ruling or scribing devices for scribing lines on surfaces. More particularly, it relates to scribing lines on sheet material at a predetermined distance from reference points.

In the aircraft industry, considerable quantities of sheet metal are used in the construction of aircraft covering or skins. These are made up in sections and customarily fastened together by means of rivets. The sheets are not pre-cut to size, due to the many compound curves used in fabricating such skins and also because of other factors, but are first provided with rivet holes by the use of jigs or in any other convenient fashion. The sheets are then cut off at a predetermined distance from the rivet holes. In order to accomplish this, it has been customary to use conventional straight edges to mark the sheets at the cut-off points. This procedure occupies a considerable amount of time, and is also subject to errors in application.

It is therefore an object of this invention to provide a ruling or scribing device which will enable a line to be quickly and accurately scribed at a predetermined distance from reference points, particularly rivet holes. Other objects will appear hereinafter.

These objects are accomplished by means of a tool having a pair of jaws, with a scribing point fixed in one of the jaws at a predetermined distance from the face of the jaw, and the other jaw being spring pressed towards the first jaw. A line is scribed on a sheet by moving the tool so that the jaws successively engage a series of temporary fasteners located in the rivet holes.

In the drawings:

Figure 1 is a perspective view of a scribing device in accordance with the present invention; Figure 2 is a top plan view of the device shown in Figure 1, in the process of scribing a line on a sheet; Figure 3 is a side elevational view of the device shown in Figure 1; Figure 4 is a section taken along the line 44 of Figure 2; and Figure 5 is a section taken along the line 5--5 of Figure 3.

Referring now to the drawing, the scribing tool, indicated generally at l0, comprises a fixed jaw I I in which is securely fastened such as by means of a press fit, a scribing needle 12. The point of this scribing needle extends slightly below the lower surface of the jaw II. A second or movable jaw I3 is held in cooperative relationship with jaw II by means of bolts I4 passing through the upper portions of jaws H and I3. The two jaws are urged towards each other by means of compression springs l5, but are prevented from too close approach by means of spacer 16, through which bolts It also pass. The faces 23 of the jaws I! and I3, as closest approach (or closed position) thus define a space between them. The width of this space, for reasons hereinafter pointed out, bears a definite relationship to the diameter of fasteners 22. The intermediate portions of the faces 23 are substantially parallel, but the extremities are provided with tapered portions I! and [8, for reasons hereinafter pointed out.

The scribing tool may be used to scribe a line l9 on a sheet 20 fastened to a second sheet 2| by means of a series of temporary fastener 22. The spacing of the jaws II and I3 should be suchthat, in their closed position, as limited by the spacerlfi, the width of the space between the two faces 23 is less than the diameter of the fastening devices 22, except at the tapered end portions I1 and I8. At the latter points, the width of the space is greater than the diameter of the fastening devices 22. This construction allows the first fastening device 22 to be easily entered between the jaws at the start of the scribing operation, and at the same time insures that the jaw l I is at all times in firm contact with two or more of the fastening devices 22. The springs I5 permit the free use of the tool, even though there is a misalignment in long rows of fasteners. In operation, the tool is merely moved along the row of fasteners, as shown in Figure 2. In order to insure proper orientation of the tool, it is important that the jaws II and I3 be of suificientlength that they are at all times in engagement with at least two fastening devices 22.

The above discussion has been inconnection with a specific form of the invention. It is obvious, however, that many changes may be made in this form without departing from the spirit of the invention. It is to be understood, therefore, that the invention is not to be limited except as defined in the appended claim.

I claim:

A device for scribing-lines on surfaces at a predetermined distance from a series of protuberances from such surfaces, comprising a pair of cooperating jaws adapted to simultaneously engage at least two of said protuberances, said jaws having faces with intermediate portions substantially parallel to each other, a tapering end on at least one of said jaws, spring means urging said jaws towards each other, a spacer element between said jaws defining a space between said faces in the closest position thereof, and a scribing point fixed to one of said jaws, the width of the space between said faces in said closed position thereof being less than the diameter of said protuberances at said intermediate portions and being greater than the diameter of said protuberances at said tapering end portion.

ALFRED JAMES LYNEX, 

